1. Field of the Invention
The invention relates to a method of low-pass filtering by means of averaging and to an arrangement for performing such a method.
2. Description of the Related Art
In a digital low pass filtering method known as "moving average" (and described, for example, by Peter Haberacker in his book "Digitale Bildverarbeitung: Grundlagen und Anwendungen", Carl Hanser Verlag, Munich/Vienna) a filtered signal value is derived from a signal value and a fixed number of adjacent values which jointly form a kernel of signal values by forming the arithmetic average value of this kernel. The term "kernel" is understood to mean a part of the signal consisting of a plurality of adjacent signal values. In order to generate a sequence of such filtered values, the kernel is shifted relatively to the signal by adding a signal value at one side of the kernel and eliminating a signal value at the other side. The length of the kernel defines the filter action. If the kernel length is large, there is a strong signal smoothing, but signal transients are obliterated. If the kernel length is small, there is a weaker smoothing, but a better display of signal transients.